There are some very good suggestions here. Usually when I build a pedal on Vero which doesn't work it takes me less than a minute to work out why. It's usually me rushing and putting a resistor one row too high or something. Sometimes I'll leave a component out. And sometimes it's as simple as installing the IC upside down or even not at all!
With PCBs it takes me a little bit longer but I'm often surprised at how quickly I can work it out by checking that everything connects where it should and checking that the bits have continuity where they should. I'm surprised at how often I have had to add a wire bridge to a PCB because there is no continuity where it should be on the board. And when I say how often I mean maybe 1-2%! I figure PCBs should be perfect, and sometimes they aren't.
With PCBs it takes me a little bit longer but I'm often surprised at how quickly I can work it out by checking that everything connects where it should and checking that the bits have continuity where they should. I'm surprised at how often I have had to add a wire bridge to a PCB because there is no continuity where it should be on the board. And when I say how often I mean maybe 1-2%! I figure PCBs should be perfect, and sometimes they aren't.